1. Field of the Invention
The present disclosure relates to medical devices, systems and methods, and more specifically to methods, systems and devices used for knotless suturing of tissue.
Soft tissue such as tendons, ligaments and cartilage are generally attached to bone by small collagenous fibers which are strong, but which nevertheless still can tear due to wear or disease. Examples of musculoskeletal disease include a torn rotator cuff as well as a torn labrum in the acetabular rim of a hip joint or the glenoid rim in a shoulder joint.
Thus, treatment of musculoskeletal disease may involve reattachment of torn ligaments, tendons or other tissue to bone. This may require the placement of devices such as suture anchors within bone. A suture anchor is a device which allows a suture to be attached to tissue such as bone. Suture anchors may include screws or other tubular fasteners which are inserted into the bone and anchored in place. After insertion of the anchor, the tissue to be repaired is captured by a suture, the suture is attached to the anchor (if not already pre-attached), tension is adjusted, and then the suture is often knotted so that the tissue is secured in a desired position.
Most conventional suture anchors require the surgeon to tie knots in the suture to secure the target tissue to the bone after the anchor is placed. Knot tying can be difficult during surgery, particularly if working in a confined space through cannulas or other surgical ports as in arthroscopic surgery. Therefore, it would be desirable to provide knotless suture anchor systems.
Additionally, many surgeons prefer to use polymeric anchors rather than metal ones so that the anchors are compatible with the use of MRI. While polymeric anchors are available, they do not have the knotless suture securing capabilities described above. This may be in part due to challenges of fabricating polymer anchors that provide a reliable cinching mechanism for a knotless anchor at the small scale required for orthopedic procedures. Further, while it is frequently advantageous to fabricate polymeric devices by molding, known knotless anchor designs require multiple moving parts and geometries which are not suitable for molding. Therefore it would be advantageous to provide a knotless anchor with the characteristics described above and which is also suitable to being molded with a polymer as a single integral part or as series of molded components that can be easily assembled together. By single integral part, it is meant that the entire part is formed from a single piece of material or molded as a single piece, without need for fastening, bonding, welding or otherwise interconnecting multiple components together. Examples of this include, but are not limited to, single-piece components that are injection molded, cast, or machined from a single block of material. The word “molded” is intended to encompass materials which are injection molded, blow molded, compression molded, thermoformed, or made using other molding processes known to those of skill in the art, useful for shaping polymers, ceramics, or other formable materials.
Frequently two or more anchors and multiple lengths of suture are required. Using such devices can be time consuming and difficult to undertake in the tight space encountered during endoscopic surgery and sometimes even in conventional open surgery. Recently, knotless suture anchors having suture clamping mechanisms have been developed to eliminate the need to tie knots but they still can be difficult or awkward to use.
Some knotless suture anchors have been devised which allow the suture to be cinched and secured without tying a knot, however these typically rely upon trapping the suture between the anchor and the bone to secure the suture, which means the anchor cannot be fully inserted into the bone until the tissue has been captured and secured tightly. The process of maintaining tension on the suture, keeping the tissue at the desired location and simultaneously inserting the anchor into the bone is difficult. Other knotless anchors rely on the manual actuation of some type of moving part on the anchor to clamp or trap the suture within the anchor, requiring an extra hand that the surgeon may not have available. It would be desirable to allow the anchor to be fully inserted in the bone prior to securing the tissue and to avoid the requirement of extra manipulations to secure the suture.
Thus, it would be desirable to provide improved knotless suture anchors that are easier to use and also that may take up less space during deployment and that are easier to deploy.
In particular, treating musculoskeletal disease in a hip joint can be especially challenging. The hip joint is a deep joint surrounded by a blanket of ligaments and tendons that cover the joint, forming a sealed capsule. The capsule is very tight thereby making it difficult to advance surgical instruments past the capsule into the joint space. Also, because the hip joint is a deep joint, delivery of surgical instruments far into the joint space while still allowing control of the working portions of the instrument from outside the body can be challenging. Additionally, the working space in the joint itself is very small and thus there is little room for repairing the joint, such as when reattaching a torn labrum to the acetabular rim. Moreover, when treating a torn labrum, the suture anchor must be small enough to be inserted into the healthy rim of bone with adequate purchase, and the anchor also must be short enough so that it does not protrude through the bone into the articular surface of the joint (e.g. the acetabulum). Existing anchors may be used to repair the labrum, but are not well-suited to labral repair especially in the hip. First, the reattachment of the labrum to the acetabular rim is most effective if both ends of the suture are attached to the same point in the bone. This provides the most precise and secure apposition of the labrum to the rim. The space available on the acetabular rim is very limited, typically requiring an anchor with a transverse dimension (e.g. diameter) preferably less than 4 mm and no more than about 3.5 mm and therefore many commercially available anchors are too large. Thus, it would be desirable to provide suture anchors that have a small diameter and length.
Additionally, existing knotless anchors are typically designed for use in rotator cuff repair in the shoulder and they are intended for placement in separate holes in the bone. These devices have no mechanism for coupling one anchor to the other within the same hole, cannot be implanted concentrically within the hole, and are too long for stacking within the same hole. Further, many existing knotless anchors are too large for placement on the acetabular rim for labral repair of the hip.
In addition, existing knotless anchors and interconnecting anchors have suture locking mechanisms which have moving parts and other complex designs that are not reliably manufacturable at the small scale required for labral repair anchors. While various types of anchors with suture locking mechanisms have been disclosed, many of these cannot be made in an anchor less than 4 mm, and no more than 3.5 mm in diameter.
Moreover, because of the difficulty of performing labral repairs arthroscopically, it is highly desirable to minimize the manipulations of the suture and anchor that are required intraoperatively. Many existing knotless anchors require the surgeon, after initial anchor placement and capture of the labrum, to thread the free end of the suture through the anchor or a component of the anchor, which is difficult and takes an excessive amount of time. Some anchors further require the surgeon to push the anchor further into bone, or push a locking mechanism on the anchor, or perform some other manipulation of the anchor in order to lock the suture. These manipulations add difficulty and time to arthroscopic labral repair that would be desirably avoided.
Therefore, it would be desirable to provide improved knotless suture anchors that are ideally suited to arthroscopic procedures, and in particular labral repair in the hip. The anchors would preferably be adapted for placement in a single hole in the bone, extremely simple in design with few or no moving parts, manufacturable at very small scale (e.g. diameter less than 4 mm, and preferably no more than 3.5 mm), and ideally be moldable as a single part or a few easily assembled parts. Further, once the suture has been tightened as desired, the anchor should automatically lock the suture in place without requiring tying or manipulation of the suture or any mechanisms on the anchor itself. The anchors should further require no intraoperative threading or tying of the suture ends before or after initial anchor placement.
Thus, there is a need for improved devices, systems and methods which overcome some of the aforementioned challenges. At least some of these objectives will be met by the inventions described hereinbelow.
2. Description of the Background Art
Patents disclosing suture anchoring devices and related technologies include U.S. Pat. Nos. 7,566,339; 7,390,329; 7,309,337; 7,144,415; 7,083,638; 6,986,781; 6,855,157; 6,770,076; 6,767,037; 6,656,183; 6,652,561; 6,066,160; 6,045,574; 5,810,848; 5,728,136; 5,702,397; 5,683,419; 5,647,874; 5,630,824; 5,601,557; 5,584,835; 5,569,306; 5,520,700; 5,486,197; 5,464,427; 5,417,691; and 5,383,905. Patent publications disclosing such devices include U.S. Patent Publication Nos. 2009/0069845 and 2008/0188854 and PCT Publication No. 2008/054814.